This invention relates to power generating apparatus using radiant energy, and more particularly, to such apparatus in which devices of the general type known as "radiometers" are put to practical use.
A number of proposals have been made for apparatus capable of converting radiant energy, most notably solar energy, directly into mechanical or electrical energy for useful purposes. Examples of apparatus proposed for this purpose may be found in the following U.S. Patents, amoung others: No. 3,031,852, issued May 1, 1962, to White; No. 3,048,006, issued Aug. 7, 1962, to Goodman; No. 3,137,125, issued June 16, 1964, to Kyryluk; and No. 3,348,374, issued Oct. 24, 1967, to Schalkowsky.
U.S. Pat. No. 182,172, issued Sept. 12, 1876, to Crookes, described the device which has come to be known as a radiometer, an instrument in which radiation is detected and made measurable by movement of a surface suspended within a partly evacuated vessel. Thus, radiometers have long been known as laboratory curiosities, or, on a more practical level, as means for measuring the intensity of radiation (see, for example, U.S. Pat. No. 1,000,831 issued Aug. 15, 1911, to Martin). Although it has been proposed that radiometer-like devices be used to produce useful work in special applications, such as the space application disclosed in U.S. Pat. No. 3,348,374, issued Oct. 24, 1967, to Schalkowsky, the conventional view has been that radiometers are incapable of useful work, at least in ordinary environments. See, for example, the abovementioned patent to Kyryluk, column 1, lines 10-17.
It is a principal object of the present invention to provide apparatus wherein the principles of the radiometer are applied to produce useful work.
It is another object of this invention to provide apparatus wherein a radiometer provides useful mechanical energy, either directly by mechanical linkage, or through an intermediary electrical device.
In a broad aspect, it is an object of this invention to provide an inexpensive, practical and reasonably efficient means for converting radiation energy, such as solar energy, to useful work.
Other objects will appear hereinafter.
The foregoing and other objects of this invention are realized, in one presently preferred form of the invention (which constitutes the best mode presently contemplated for carrying out the invention), by apparatus which comprises a radiation-transparent housing, a drive rotor mounted in the housing for rotation therein, and a plurality of circumferentially spaced longitudinally extending vanes disposed on the rotor, each vane having one dark and one light surface and the drive rotor being coupled to mechanical or electrical power take-off means. As is known in the art, the torque created by a radiometer may be varied as a function of the gas pressure within the housing and the length of the moment arm to the centroid of the vane. Thus it is also, contemplated, in accordance with the preferred form of the present invention, that an operator be provided with means for regulating gas pressure within the housing, to thereby control the output of the apparatus.